Unbilled Receivables:	12 Months Ended
Sep. 30, 2014
Unbilled Receivables:
Unbilled Receivables:	5. Unbilled Receivables: Unbilled receivables principally represent sales recorded under the percentage-of-completion method of accounting that have not been billed to customers in accordance with applicable contract terms. Unbilled receivables, net of progress payments and recorded an impairment for unbilled receivables of $3.7 million related to the Delta contract, were $7.4 million at September 30, 2014 (See Note 14. Commitments and Contingencies). Unbilled receivables, net of progress payments were $6.5 million at September 30, 2013. The unbilled receivables recorded under the Delta contract were $3.7 million and $774,000 at September 30, 2014 and 2013, respectively. The percentage-of-completion method of accounting for EDC revenue, requires estimates of profit margins for contracts be reviewed by the Company on a quarterly basis. If the initial estimates of revenues and costs under a contract are accurate, the percentage-of-completion method results in the profit margin being recorded evenly as revenue is recognized under the contract. Changes in these underlying estimates because of revisions in revenue and cost estimates or the exercise of contract options may result in profit margins being recognized unevenly over a contract because such changes are accounted for on a cumulative basis in the period in which the estimates are revised. Significant changes in estimates related to accounting for long-term contracts may have a material effect on the Company’s results of operations in the period in which the revised estimates are made. Net cumulative catch-up adjustments resulting from changes in estimates reduced operating income by $1.5 million, $444,000 and $8,000 during fiscal years ended September 30, 2014, 2013 and 2012, respectively.

5. Unbilled Receivables:

Unbilled receivables principally represent sales recorded under the percentage-of-completion method of accounting that have not been billed to customers in accordance with applicable contract terms. Unbilled receivables, net of progress payments and recorded an impairment for unbilled receivables of $3.7 million related to the Delta contract, were $7.4 million at September 30, 2014 (See Note 14. Commitments and Contingencies). Unbilled receivables, net of progress payments were $6.5 million at September 30, 2013. The unbilled receivables recorded under the Delta contract were $3.7 million and $774,000 at September 30, 2014 and 2013, respectively.

The percentage-of-completion method of accounting for EDC revenue, requires estimates of profit margins for contracts be reviewed by the Company on a quarterly basis. If the initial estimates of revenues and costs under a contract are accurate, the percentage-of-completion method results in the profit margin being recorded evenly as revenue is recognized under the contract. Changes in these underlying estimates because of revisions in revenue and cost estimates or the exercise of contract options may result in profit margins being recognized unevenly over a contract because such changes are accounted for on a cumulative basis in the period in which the estimates are revised. Significant changes in estimates related to accounting for long-term contracts may have a material effect on the Company’s results of operations in the period in which the revised estimates are made. Net cumulative catch-up adjustments resulting from changes in estimates reduced operating income by $1.5 million, $444,000 and $8,000 during fiscal years ended September 30, 2014, 2013 and 2012, respectively.